Investigation of the mechanisms of Escherichia coli cells sterilization by the application of an electric field

Abstract

The inactivation of microorganisms by an electric field was the purpose of this study. It was found that the application of an electric field had a lethal effect on Escherichia coli cells suspended in brain heart infusion broth. Experimental results indicated that the survival rate of E. coli decreased when an electric field with an intensity of 3A was applied during a time equal to 30 min. Mechanisms involved in the sterilization process were discussed. The concentration of proteins and N-acetylglucosamine (NAG) liberated by the cells during the experiment was recorded. The results indicated that the concentration of liberated proteins was 2.21 µg/ml after 5 min, and this concentration increased twofold after 45 min (4.10 µg/ml). The initial concentration of NAG was 0.084 µg/ml. It increased to 0.1 µg/ml after 5 min, to 0.2 µg/ml after 10 min and to 1.3 µg/ml after 30 min.